HInnerAllocatedObject instruction allows hydrogen code to carve up
allocated regions into sub objects.

BUG=

Review URL: https://codereview.chromium.org/12812002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@13928 ce2b1a6d-e550-0410-aec6-3dcde31c8c00